Comment:

The Value Set Definition standard slated to go normative has a element called CLDSyntaxReference. This is a a link or identifiable name for the syntax used in the Content Logical Definition Content Expression.

FHIR does not support multiple defining syntaxes in ValueSet.compose. It does have special capatbilities to handle the value sets commonly defined using SNOMED CT with the SCT expresssion constraint langguage. Value sets defined in other syntaxes that are available from external publishers defined with a non-SNOMED type syntax that has not been explicitly added to FHIR cannot be represented in ValueSet.compose. We do not see any way that such a value set can be "brought in" by reference using compose.include.valueset either. FHIR does meet the need for the HL7 product families and for SNOMED. Outside of that, it is unclear.

For example, using a syntax that either crosses multiple code systems, uses properties/operations not defined by the code system (such as Child-Of within ICD) and/or includes another value set composed of codes from multiple codesystems as the target (Rob M will use the TQL ICD Child-Of example in his tracker item).

Relatedly, concrete examples of how excludes work in tandem with includes need to be added. For example, given a compose.include with multiple value sets (VS A and VS B which have members from multiple codesystems, including code system A), how is the exclude used to remove code system A concepts from VS A membership only.

Please note, all of the items in this ballot require resolution at the vocab work group call

Summary:

Add support for VSD CLDSyntaxReference